printk: allocate kernel log buffer earlier
On larger systems, because of the numerous ACPI, Bootmem and EFI messages,
the static log buffer overflows before the larger one specified by the
log_buf_len param is allocated. Minimize the overflow by allocating the
new log buffer as soon as possible.
On kernels without memblock, a later call to setup_log_buf from
kernel/init.c is the fallback.
[akpm@linux-foundation.org: coding-style fixes]
[akpm@linux-foundation.org: fix CONFIG_PRINTK=n build]
Signed-off-by: Mike Travis <travis@sgi.com>
Cc: Yinghai Lu <yhlu.kernel@gmail.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Jack Steiner <steiner@sgi.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index 605e5ae..a3e5948 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -946,6 +946,8 @@
if (init_ohci1394_dma_early)
init_ohci1394_dma_on_all_controllers();
#endif
+ /* Allocate bigger log buffer */
+ setup_log_buf(1);
reserve_initrd();
diff --git a/include/linux/printk.h b/include/linux/printk.h
index ee048e7..0101d55 100644
--- a/include/linux/printk.h
+++ b/include/linux/printk.h
@@ -1,6 +1,8 @@
#ifndef __KERNEL_PRINTK__
#define __KERNEL_PRINTK__
+#include <linux/init.h>
+
extern const char linux_banner[];
extern const char linux_proc_banner[];
@@ -113,6 +115,7 @@
extern int kptr_restrict;
void log_buf_kexec_setup(void);
+void __init setup_log_buf(int early);
#else
static inline __attribute__ ((format (printf, 1, 0)))
int vprintk(const char *s, va_list args)
@@ -137,6 +140,10 @@
static inline void log_buf_kexec_setup(void)
{
}
+
+static inline void setup_log_buf(int early)
+{
+}
#endif
extern void dump_stack(void) __cold;
diff --git a/init/main.c b/init/main.c
index 22da339..d2f1e08 100644
--- a/init/main.c
+++ b/init/main.c
@@ -504,6 +504,7 @@
* These use large bootmem allocations and must precede
* kmem_cache_init()
*/
+ setup_log_buf(0);
pidhash_init();
vfs_caches_init_early();
sort_main_extable();
diff --git a/kernel/printk.c b/kernel/printk.c
index da8ca81..3518539 100644
--- a/kernel/printk.c
+++ b/kernel/printk.c
@@ -31,6 +31,7 @@
#include <linux/smp.h>
#include <linux/security.h>
#include <linux/bootmem.h>
+#include <linux/memblock.h>
#include <linux/syscalls.h>
#include <linux/kexec.h>
#include <linux/kdb.h>
@@ -167,46 +168,74 @@
}
#endif
+/* requested log_buf_len from kernel cmdline */
+static unsigned long __initdata new_log_buf_len;
+
+/* save requested log_buf_len since it's too early to process it */
static int __init log_buf_len_setup(char *str)
{
unsigned size = memparse(str, &str);
- unsigned long flags;
if (size)
size = roundup_pow_of_two(size);
- if (size > log_buf_len) {
- unsigned start, dest_idx, offset;
- char *new_log_buf;
+ if (size > log_buf_len)
+ new_log_buf_len = size;
- new_log_buf = alloc_bootmem(size);
- if (!new_log_buf) {
- printk(KERN_WARNING "log_buf_len: allocation failed\n");
- goto out;
- }
-
- spin_lock_irqsave(&logbuf_lock, flags);
- log_buf_len = size;
- log_buf = new_log_buf;
-
- offset = start = min(con_start, log_start);
- dest_idx = 0;
- while (start != log_end) {
- log_buf[dest_idx] = __log_buf[start & (__LOG_BUF_LEN - 1)];
- start++;
- dest_idx++;
- }
- log_start -= offset;
- con_start -= offset;
- log_end -= offset;
- spin_unlock_irqrestore(&logbuf_lock, flags);
-
- printk(KERN_NOTICE "log_buf_len: %d\n", log_buf_len);
- }
-out:
- return 1;
+ return 0;
}
+early_param("log_buf_len", log_buf_len_setup);
-__setup("log_buf_len=", log_buf_len_setup);
+void __init setup_log_buf(int early)
+{
+ unsigned long flags;
+ unsigned start, dest_idx, offset;
+ char *new_log_buf;
+ int free;
+
+ if (!new_log_buf_len)
+ return;
+
+ if (early) {
+ unsigned long mem;
+
+ mem = memblock_alloc(new_log_buf_len, PAGE_SIZE);
+ if (mem == MEMBLOCK_ERROR)
+ return;
+ new_log_buf = __va(mem);
+ } else {
+ new_log_buf = alloc_bootmem_nopanic(new_log_buf_len);
+ }
+
+ if (unlikely(!new_log_buf)) {
+ pr_err("log_buf_len: %ld bytes not available\n",
+ new_log_buf_len);
+ return;
+ }
+
+ spin_lock_irqsave(&logbuf_lock, flags);
+ log_buf_len = new_log_buf_len;
+ log_buf = new_log_buf;
+ new_log_buf_len = 0;
+ free = __LOG_BUF_LEN - log_end;
+
+ offset = start = min(con_start, log_start);
+ dest_idx = 0;
+ while (start != log_end) {
+ unsigned log_idx_mask = start & (__LOG_BUF_LEN - 1);
+
+ log_buf[dest_idx] = __log_buf[log_idx_mask];
+ start++;
+ dest_idx++;
+ }
+ log_start -= offset;
+ con_start -= offset;
+ log_end -= offset;
+ spin_unlock_irqrestore(&logbuf_lock, flags);
+
+ pr_info("log_buf_len: %d\n", log_buf_len);
+ pr_info("early log buf free: %d(%d%%)\n",
+ free, (free * 100) / __LOG_BUF_LEN);
+}
#ifdef CONFIG_BOOT_PRINTK_DELAY